Concurrence of longitudinal melanonychia and numbness in a patient with left hemiparesis suffering from thumb injury by clamp during performing occupational therapy

Numbness within the thumb involving the palmar aspect with the three and a half digits as the division is a common presentation of peripheral nerve injury. However, it is rarely observed to be presented with numbness at half of the ulnar-palmar side of the thumb, where the longitudinal melanonychia on the nail plate acts as the division. We present a case that reveals concurrence of longitudinal melanonychia and numbness suffered from a thumb injury during the course of occupational therapy.